Light guide employing multilayer optical film

• US RE37,594 E1
• Filed: 08/11/1999
• Issued: 03/19/2002
• Est. Priority Date: 03/22/1996
• Status: Expired due to Term

• Current Assignee: University of British Columbia
• Original Assignee: University of British Columbia
• Inventors: Whitehead, Lorne A.
• Primary Examiner(s): Palmer, Phan T. H.
• Application Number:
  US09/370,507
• Time in Patent Office: 951 Days
• Field of Search: 385/131, 385/130, 385/132, 385/133, 385/901, 362/551, 362/558, 362/559, 362/560
• US Class Current: 385/131
• CPC Class Codes: G02B 5/285 comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361
• CPC Class Codes: G02B 5/287 comprising at least one layer of organic material
• CPC Class Codes: G02B 5/305 including organic materials, e.g. polymeric layers
• CPC Class Codes: G02B 6/001 the light being emitted along at least a portion of the lateral surface of the fibre
• CPC Class Codes: G02B 6/0096 the lights guides being of the hollow type
• CPC Class Codes: G02B 6/2804 forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

A light guide having a non-light emitting portion made up of multiple layers of first and second substantially non-absorptive longitudinally specular light reflector materials. The index of refraction of each layer differs from the indices of refraction of the immediately adjacent layers, such that the layers collectively have high longitudinally specular reflectivity. The light guide also has a light emitting portion made of prism light guide wall material. A substantially non-absorptive light scattering mechanism is positioned within the non-light emitting portion in opposition to the light emitting portion.

Claims

1. A light guide, comprising in cross-section:

(a) a non-light emitting portion comprising multiple layers of;

(i) a first substantially non-absorptive longitudinally specular light reflector;

(ii) a second substantially non-absorptive longitudinally specular light reflector;

each one of said layers having a selected index of refraction which differs from the indices of refraction of layers immediately adjacent said one of said layers, such that said multiple layers collectively have high longitudinally specular reflectivity;

(b) a light emitting portion comprising prism light guide wall material; and

,

(c) a substantially non-absorptive light scattering means positioned within said non-light emitting portion in opposition to said light emitting portion.

2. A light guide as defined in claim 1, wherein:

(a) said light guide cross-section is substantially constant along said light guide; and

,

(b) said light scattering means has a width which increases as a function of length along said light guide.

3. A light guide as defined in claim 1, wherein:

(a) said light guide cross-section decreases as a function of length along said light guide; and

,

(b) said light scattering means has a width which increases as a function of length along said light guide.

4. A light guide as defined in claim 1, further comprising a lens positioned outside said light emitting portion, said lens characterized by:

(a) low light absorption; and

,

(b) light transmissivity which varies as a function of one or more of;

(i) wavelength;

(ii) polarization; and

,

(iii) angle.

5. A light guide as defined in claim 1, further comprising an opaque cover surrounding and bonded to said non-light emitting portion.

6. A light guide as defined in claim 1, wherein said light scattering means comprises a non-absorptive, single textured air-polymer interface bonded to said non-light emitting portion by a non-absorptive adhesive.

7. A light guide as defined in claim 1, wherein each of said layers has a thickness of no more than 0.5 microns.

8. A light guide, comprising in cross-section:

(a) a non-light emitting portion comprising layers of first and second substantially non-absorptive polymers, said first and second polymers differing in composition such that said layers collectively have high longitudinally specular reflectivity;

(b) a light emitting portion comprising prism light guide wall material; and

,

(c) a substantially non-absorptive light scattering means positioned within said non-light emitting portion in opposition to said light emitting portion.

9. A light guide as defined in claim 8, wherein:

(a) said light guide cross-section is substantially constant along said light guide; and

,

(b) said light scattering means has a width which increases as a function of length along said light guide.

10. A light guide as defined in claim 8, wherein:

(a) said light guide cross-section decreases as a function of length along said light guide; and

,

(b) said light scattering means has a width which increases as a function of length along said light guide.

11. A light guide as defined in claim 8, further comprising a lens positioned outside said light emitting portion, said lens characterized by:

(a) low light absorption; and

,

(b) light transmissivity which varies as a function of one or more of;

(i) wavelength;

(ii) polarization; and

,

(iii) angle.

12. A light guide as defined in claim 8, further comprising an opaque cover surrounding and bonded to said non-light emitting portion.

13. A light guide as defined in claim 8, wherein said light scattering means comprises a non-absorptive, single textured air-polymer interface bonded to said non-light emitting portion by a non-absorptive adhesive.

14. A light guide as defined in claim 8, wherein each of said layers has a thickness of no more than 0.5 microns.

15. A light guide, comprising in cross-section:

(a) a non-light emitting portion comprising multiple layers of;

(i) a first substantially non-absorptive longitudinally specular light reflector;

(ii) a second substantially non-absorptive longitudinally specular light reflector;

each one of said layers having a stress induced birefringence such that said multiple layers are birefringent over a range of uniaxial to biaxial orientation of said layers and such that said multiple layers collectively have high longitudinally specular reflectivity;

(b) a light emitting portion comprising prism light guide wall material; and

,

(c) a substantially non-absorptive light scattering means positioned within said non-light emitting portion in opposition to said light emitting portion.

16. A light guide as defined in claim 15, wherein:

(a) said light guide cross-section is substantially constant along said light guide; and

,

(b) said light scattering means has a width which increases as a function of length along said light guide.

17. A light guide as defined in claim 15, wherein:

(a) said light guide cross-section decreases as a function of length along said light guide; and

,

(b) said light scattering means has a width which increases creases as a function of length along said light guide.

18. A light guide as defined in claim 15, further comprising a lens positioned outside said light emitting portion, said lens characterized by:

(a) low light absorption; and

,

(b) light transmissivity which varies as a function of one or more of;

(i) wavelength;

(ii) polarization; and

,

(iii) angle.

19. A light guide as defined in claim 15, further comprising an opaque cover surrounding and bonded to said non-light emitting portion.

20. A light guide as defined in claim 15, wherein said light scattering means comprises a non-absorptive, single textured air-polymer interface bonded to said non-light emitting portion by a non-absorptive adhesive.

21. A light guide as defined in claim 15, wherein each of said layers has a thickness of no more than 0.5 microns.

22. A light guide, comprising in cross-section:

(a) a non-light emitting portion comprising multiple layers, each one of said layers having a selected index of refraction which differs from the indices of refraction of layers immediately adjacent said one of said layers, such that said multiple layers collectively have high longitudinally specular reflectivity; and

,

(b) a light emitting portion comprising prism light guide wall material.

23. A light guide, comprising in cross-section:

(a) a non-light emitting portion comprising layers of first and second substantially non-absorptive polymers, said first and second polymers differing in composition such that said layers collectively have high longitudinally specular reflectivity; and

,

(b) a light emitting portion comprising prism light guide wall material.

24. A light guide, comprising in cross-section:

(a) a non-light emitting portion comprising multiple layers, each one of said layers having a stress induced birefringence such that said multiple layers are birefringent over a range of uniaxial to biaxial orientation of said layers and such that said multiple layers collectively have high longitudinally specular reflectivity; and

,

(b) a light emitting portion comprising prism light guide wall material.

25. A light guide, comprising in cross-section:

(a) a non-light emitting portion comprising multiple layers, each one of said layers having a stress induced birefringence such that said multiple layers are birefringent over a range of uniaxial to biaxial orientation of said layers and such that said multiple layers collectively have high longitudinally specular reflectivity;

(b) a light emitting portion comprising prism light guide wall material; and

,

(c) a substantially non-absorptive light scattering means positioned within said non-light emitting portion in opposition to said light emitting portion.